package com.zhangrui.utils;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.InputStream;

/**
 * ClassName:MybatisUtils
 * Package:com.zhangrui.utils
 * Description:
 *
 * @Date:2021/8/1112:55
 * @Author:zhangrui@qq.com
 */
//sqlSessionFactory -----> sqlSession
//一下代码就做了两件事情，把数据库的核心配置文件加载进来，然后创建一个可以调用数据库的一个对象实例
public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;

    static {
        String resource = "mybatis-config.xml";
        try {
            //获取sqlSessionFactory对象的!!!!!
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //既然有了SqlSessionFactory，顾名思义，我们就可以从中获取SqlSession的实例了
    //SqlSession完全包含了面向数据库执行SQL命令的所需的所有方法
    public static SqlSession getSqlSession() {
        SqlSession sqlSession = sqlSessionFactory.openSession();
        return sqlSession;
    }
}
